Methods :
In this retrospective and longitudinal study, 38 eyes of 38 patients who underwent AGV implantation with modified tube ligation were observed at least 6 months after the surgery. After priming of the valve, the tube was ligated using temporary 6-0 prolene intraluminal stent and 8-0 vicryl ligature.Intracameral injection of viscoelastics was done at the end of the surgery when intraocular pressure (IOP) was lower than 10mmHg with Tono-pen tonometry or anterior chamber became shallow during procedures.Hypotony was defined as IOP < 6 mmHg.

Results :
Intracameral viscoelastic injection was done in 20 eyes during the procedure. The early postoperative hypotony developed in 5 of 38 eyes (13.2%) and lasted mean 10.0 ± 10.3 days (1 to 28 days). None of themrequired any surgical intervention related to hypotony. IOP was higher than 21 mmHg in 4 eyes (10.5%) on the first postoperative day. Three of them recovered to normal IOP in a day without any surgical intervention.However, one of them required laser suture lysis to normalize IOP. IOP of postoperative 1 week was significantly lower than that of day 1 in viscoelastic injection group (p<0.01) but not in non-injection group. Statistical analyses including Wilcoxon signed rank test were performed to compare the preoperative and postoperative IOP. χ2 test was used for comparing occurrence rate of hypotony, hypertensive phase and postoperative hypertension between groups.